Caution: These are not DIY projects for beginners. High voltages are involved that can kill you. Do not attempt to build
these (or any other similar high-voltage) circuits if you don't know what you're doing. This site is not a how-to guide for newbies,
but rather a resource for experienced electronics hobbyists.

08/08/07 - I recorded this clip very quickly to experiment with a chord riff I had come up with. It's all '57 Stratocaster USA Reissue through the Tweed repro, no effects - other than a volume pedal and little Ambience reverb on the melody guitar. Not a great recording but some really nice funk tone: Panned right is the Strat rhythm, left is the Strat playing the bass line; hard right are Strat fills, center is the Strat playing melody. 4 Strat/Tweed tracks in all; Shure SM57 -> Redd.47 -> Pultec EQ (flat) -> La2a (compressing about -3dB).

Recently, I was considering building an 18 Watt clone or buying a new Marshall 1974x combo (or 2061x) Bluesbreaker amp, as I had come across a great sounding demo on YouTube. Then I thought to record a quick video demo with the Fender (cranked) to see how it stacked up.

Both circuits are extremely simple and rather close in design, so one might expect the individual experiences to yield similarities, and they do. Sounds like the Marshall has quite a bit of power supply sag, so I opened up the Tweed all the way and it definitely becomes much easier to play - smoother, totally compressed with more sustain - especially with both volumes and the tone control pegged while using the normal channel high input. Not quite as much gain, possibly, as the 1974x, but still singing and grinding pretty nicely with the 335's original patent-sticker (non t-top) pickups (that are not set that high). Touch sensitivity should also rival (if not surpass) the 18 watt circuit, while the clean tone (there appears to be a little more headroom with the Fender) is peerless. Also, from what I've read the Marshall can be a little loud for home use, while the Tweed is just right for me (and my neighbors, so far) with the old P12Q Jensen alnico. Then there's the cost - the Marshall and clone kits are pretty expensive, relatively. Anyway, I don't think I want (or need) the Marshall anymore. Tweed Deluxe Video.

Built in 2001, and rebuilt about 20 times. I went through Mojo transformers, a blackface choke, a Celestion Alnico Blue, a Weber P12R (smooth cone), solid state rectifiers, NOS 5V4 rectifiers, copper caps (two blew up, and one of those shocked the hell out of me (full b+) when I touched it and the chassis at the same time - a result no doubt facilitated by diode leads coming in contact with the copper enclosure; a risky design, obviously), conjunctive filter (Fender Blues Jr. and Dr. Z Prescription circuits), different capacitor and resistor values. Finally ended up with this configuration:

NOS RCA 6V6 Blackplates or Tung-Sol, NOS RCA or GE 12AX7, 12AY7, 5Y3 tubes. (Went through several sets of EH 6V6 and they were just terrible - red plates and microphonics. Settled on NOS and have had zero problems since.)

(It's essentially a 50 year old amp with a cap job. The only exceptions to a stock 5E3 are the Ampeg Mod; and varied cap values - which could be attributed to drift.)

Variac at around 105VAC. Keeps the amp cooler, the 6V6's healthier, and sounds a little better to me. Dials in the sag a little more.

Variac Info: You can't lower the voltage too much with a variac or you will damage the tubes.
This is because the heater voltage of the power transformer is also reduced by the variac, and the consensus is that if you lower (or raise) the heater voltage by more than about 5% from the 6.3VAC standard, tube life is shortened.
(However, there is also conjecture that lowering the heater voltage to perhaps 5VAC will actually extend tube life.)

I try to play it safe and run my variac at 92% of AC mains voltage. At my house (today) the wall voltage was 121VAC, my variac was putting out about 109VAC. This drop allows the amp to run much cooler, and I haven't changed tubes in years.

Keep in mind that my B+ voltage is about 385VDC. Power transformers supplying lower secondary voltages would probably negate the need for a variac - notwithstanding the theoretical benefit of extended tube life.

A bit of sandpaper on the lacquered tweed created a nice distressed look, like it's been sliding around in the back of a station-wagon for a few years.

Over the last few months the amp started to develop it's own character. I suppose that since I stopped swapping out parts several months ago and let it be, the amp has had time to settle-in. Anyway, it does some really neat things now. 'Color' is the word that best describes it.

Regarding the Ampeg mod, or 'Paul C' mod: I went back and forth with it in and out, and the difference is subtle.

The 1955 through 1960 narrow panel Tweed Deluxe is a very simple circuit to build and a great way to get acquainted with tube circuits. Parts are readily available from a variety of sources, and more importantly, there's very little drilling and zero fabrication required. The Deluxe can be completed in as little as two days work.

Tweed Deluxes are also wonderful studio amps, used most notably by Larry Carlton (on Steely Dan's Royal Scam and Donald Fagen's The Nightfly) as well as Don Felder of the Eagles on most everything studio as well as live. Possibly the best clean sound in the world, with great overdrive.

It's amazing that this simple amplifier can provide such a wide range of tone - from Larry Carlton's clean jazz and overdriven solos to Billy Gibbons' diverse rhythm, slide and lead work with both single coils and humbuckers. (Interestingly, there is some speculation that Leslie West used a solid-state Sunn amplifier on Mountain's Mississippi Queen, but I'd guess it was a Tweed Deluxe.) Also, as many vintage tweed circuits are somewhat similar, it's possible to get very close to Jeff Baxter's tone on Steely Dan's early recordings like My Old School, as well as Joe Walsh's, on for example, Rocky Mountain Way (both purported to be Tweed Champs), not to mention David Lindley's beautiful slide work with Jackson Brown during the '70s. Of course, Neil Young is the artist most identified with the Deluxe, both solo and with Crosby, Stills, Nash and Young.

In any event, with proper lead dress the Deluxe is very quiet, even cranked up. However, due to its considerable sensitivity (from clean to clipping depending upon pick attack) it can be very difficult to play cleanly and quietly. As such, a Tweed Deluxe will definitely make you a much better player - especially in the studio - once you've got the hang of it.

I've had some time now to use both deluxes and the differences are that the new Deluxe with the Celestion Alnico is better with single coils for a Joe Walsh Life's Been Good type of tone. It's also very good with crunchy humbucker rhythm work. The Celestion Alnico Blue definitely lends a Vox tone to the amp - very tight and crisp; it is also much, much louder than the Jensen P12Q. Wide-open with the 335's treble pickup it's just fantastic (bright, high gain input with everything up all the way, and just the second volume backed off a bit to increase gain).

The old Deluxe repro is a little smoother with less bottom and sounds great with both single coils and humbuckers, but works especially well with overdriven humbucker lead work. It's also very good with both single coil and humbucker clean and mildly dirty tones. The main differences (aside from the P12Q) being the old output transformer, Ampeg mod, cap values and older NOS 6V6 RCA blackplates (of course, it's also well broken-in).

Volume Pedal:

I'll let you all in on a little secret I've found - in lieu of a proper volume pedal, I've been inserting a 500k analog pot between the guitar and Tweed amp. I can't really describe what it does to the tone, but set full-up it seems to make the amp sound a little more vintage - smoother and sweeter - and without any perceived reduction in drive or volume. Using it to back-off the volume a little results in small changes in tone that otherwise could not be achieved by plugging straight into the amp. This is a very subtle effect, but I like it so much that I always use it now with both single-coil and humbucker pickups; and in fact will be picking up a 500K volume pedal soon. Placing a potentiometer or volume pedal in line (parallel) will change the amplifier's input resistance, and this is responsible for the tonal effect (500k is the value used in the old Sho-Bud volume pedals).

To make a manual volume control: Connect the tips of 2 phone jacks to the center and left tabs on the 500k pot respectively, then ground both jacks to the right tab. Guitar->Volume Control->Amp. Photo here.